A combined biologic, biochemical, and serologic approach is being utilized to study the papilloma viruses associated with human warts. A radioimmune assay for viral antigen has been developed and is being refined. Purification of viral DNA will be accomplished for nucleic acid hybridization studies. These procedures will be used to monitor efforts to propagate virus in tissue culture as well as to evaluate the relatedness of virus in various types of warts. The relationship to other papova viruses will be explored. Skin from a variety of disorders of epidermal proliferation, including cancers associated with epidermodysplasia verruciformis, will be evaluated for the presence and expression of papilloma virus genetic material. Other malignant tissue will be studied virologically.